【摘要】 文章以汽车散热器盖板压铸件为研究对象，采用半固态压铸工艺制备铸件，并对不同工艺参数下的T6热处理进行研究。通过静拉伸和硬度试验测试其力学性能，并利用OM、SEM、EDS、XRD等表征方法揭示其强化机理。研究结果表明：在本试验范围内，较优的T6热处理工艺为350℃固溶后220℃时效3 h(220℃+3 h)，其抗拉强度达228.91 MPa，较铸态提升25%；同时，其伸长率及硬度较铸态未下降，分别达2.35%、69.46 HRF。强度的提升主要归因于时效后Mg2Si相的析出，阻碍了位错运动，起到第二相强化效应；且220℃+3 h时效后，获得的α-Al相的平均晶粒尺寸较小且圆整。T6热处理后试样仍以脆性断裂为主。更多还原

【Abstract】 This article takes the die-cast cover of an automobile radiator as the research subject,the semi-solid die casting method is used to obtain the castings,followed by T6 heat treatment with different process parameters was studied. Then,static tensile and hardness tests are conducted to evaluate their mechanical properties,and OM,SEM,EDS,and XRD characterization methods are employed to reveal the strengthening mechanism. The research results indicate that,within the scope of this experiment,the optimal T6 heat treatment process is solution treatment at 350 ℃ followed by aging at 220 ℃ for 3 hours(220 ℃+3h),achieving a tensile strength of 228.91 MPa,which is a 25% increase compared to the as-cast state. Meanwhile,the elongation and hardness do not decrease compared to the as-cast state,reaching 2.35% and 69.46 HRF,respectively. The enhancement in strength is attributed to the precipitation of Mg2 Si phase after aging,which impedes dislocation movement and exerts a secondphase strengthening effect. Moreover,after aging at 220 ℃ for 3 hours,the average grain size of the α-Al phase obtained is smaller and more rounded. After T6 heat treatment,the specimens still predominantly exhibit a brittle fracture mode.更多还原